"[Sansa has changed] from being a naive, vulnerable innocent young woman and being such an underdog... to being a leader, powerful and hungry for revenge from the people who have done her family wrong," Sophie told Yahoo Lifestyle Singapore.

"I can totally see her becoming a Cersei and kind of driven mad by it, by the threats against her family," she continued, comparing the characters by saying Sansa and Cersei are "both so family-obsessed and family-oriented" that they'll do anything for the people they love.

"At the end of the day, that's why [Cersei] does the things that she does, because she's terrified of losing the people she loves. And so she'll stop at nothing to protect them," she added.

"If that means becoming like a ruthless killer, leader, sadistic woman or evil lady, then so be it. I don't think it matters to her, and I can see Sansa swinging that way too."

"There's the smile... her walking away after killing Ramsay. That's quite interesting," she teased. "You wonder if it's just a smile because it's her first kill, because this man is out of her life, or whether she's going to get a taste for it. Whether she enjoyed it. Whether it's a power trip."

"It's really amazing to watch her grow, but now I'm a little worried because she's kind of reached a pinnacle," Sophie added. "Is it all downhill from here? Does she die now? So who knows – maybe she does."

Game of Thrones returns to HBO in the US and Sky Atlantic in the UK in July with a super-sized season premiere that will run for 59 minutes.